Thyrotoxic periodic paralysis (TPP) is an unusual complication of hyperthyroidism that may cause diagnostic difficulties due to its clinical feature that may be similar to other diseases. However, TPP can be detected early based on the weakness presentation, which generally affects the lower extremity with proximal muscle involvement, and, additionally, the ECG findings presenting hypokalemia characteristics. This case illustrates a young Indonesian male presenting in the emergency department with paralysis and typical ECG findings suggesting TPP. Early identification of TPP is necessary for executing proper treatment and reducing complications.